A generalized liquid crystal display (LCD) assembly includes an LCD (e.g., one or more glass substrates carrying a number of electrodes and liquid crystals), which is disposed between a transparent display cover and a backlight assembly. The backlight assembly typically includes a driver board, a casing sidewall, a light source, and a heat sink. The casing sidewall circumscribes the driver board and cooperates therewith to create a light cavity within the LCD assembly. The light source is electrically coupled to the driver board and, when energized, illuminates the light cavity to backlight the LCD. The light source can assume a variety of different forms including that of an incandescent bulb, an electroluminescent panel, a fluorescent lamp, or a plurality of light emitting diodes (LEDs). In the latter case (i.e., when the light source assumes the form of a plurality of LEDs), the backlight assembly may further include a printed wiring board (PWB) having a generally planar leading surface that faces the LCD when the LCD assembly is fully assembled (referred to as “the display-facing surface” herein). The LEDs may be mounted to the display-facing surface of the PWB. The PWB, in turn, may be mounted to the heat sink. In certain LCD assemblies, a diffuser film and/or at least one polarizing film may be disposed between the LCD and the backlight assembly. The diffuser film disburses the LED-produced light evenly over the rear surface of the LCD, and the polarizing film reflects light that is not oriented in the same manner as the LCD's polarizing filters.
The efficiency of a backlight assembly, and specifically the brightness of the light produced by backlight assembly relative to the power required to drive the backlight assembly, has a significant impact on the overall efficiency of the host LCD assembly. It is consequently desirable to optimize the efficiency of a backlight assembly, especially when the backlight assembly is included within an LCD assembly deployed aboard an aircraft wherein available energy may be in high demand and relatively costly to generate. The efficiency of a backlight assembly is determined, in part, by the reflectivity of the light cavity, and particularly the reflectivity of the PWB's display-facing surface, which reflects the light emitted from the LEDs toward the LCD and which also re-reflects light returned by the polarizing film. To this end, certain thermoplastic resin coatings (e.g., polytetrafluoroethylene-based coatings) have been developed that may be applied over the display-facing surface of the PWB to increase the reflectivity of the display-facing surface and, therefore, the overall reflectivity of the light cavity. Although providing a considerable increase in the reflectivity of the display-facing surface, such known thermoplastic resin coatings tend to be relatively expensive to produce and can add considerable cost in large scale manufacturing.
There thus exists an ongoing need to provide a high efficiency backlight assembly suitable for deployment within an LCD assembly or other flat panel display assembly. Ideally, such a high efficiency backlight assembly would include a highly efficient light cavity that is relatively inexpensive and straightforward to produce. It would be desirable if such a highly efficient light cavity included an optical coating overlaying the display-facing surface of the PWB that is highly reflective to visible light and that reflects light substantially evenly over the visible color spectrum. It would also be desirable to provide a method for fabricating such a high efficiency backlight assembly that fits within standard manufacturing processes and can be automated with relative ease. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and this Background.